False Positives with Spam Flood Prevention
Tier1Net has received increased reports of legitimate emails being delayed with the senders receiving a temporary failure message of “451 Exceeding Connection Limit: RBLDNSD.”
Tier1Net has traced the issue to a new Spam Flood Prevention policy recently enabled by McAfee. This new policy was designed to reduce the impact of certain spam campaigns characterized by unusual spikes in traffic over short periods of time, by withholding delivery until traffic returns to a normal threshold.
However, Tier1Net has observed a high volume of “false positive” delays, wherein McAfee identifies legitimate senders as spam campaigns.
As a result, Tier1Net has disabled the McAfee Spam Flood Prevention feature for all of its McAfee Email Protection customers.
For more information, please visit https://support.mcafeesaas.com/MCAFEE/_cs/AnswerDetail.aspx?sSessionID=16814425079KXWEWWRBBBBIZKVKUXMZPPKRORQWW&aid=271042